'''
Write a function to delete a node (except the tail) in a singly linked list,
given only access to that node.

Supposed the linked list is 1 -> 2 -> 3 -> 4 and you are given the third node
with value 3, the linked list should become 1 -> 2 -> 4 after calling your
function.
'''

# Definition for singly-linked list.
class ListNode(object):
    def __init__(self, x):
        self.val = x
        self.next = None

class Solution(object):
    def deleteNode(self, node):
        """
        :type node: ListNode
        :rtype: void Do not return anything, modify node in-place instead.
        """
        node.val = node.next.val
        node.next = node.next.next
                
            
if __name__=="__main__":
    n1 = ListNode(1)
    n2 = ListNode(2)
    n3 = ListNode(3)
    n4 = ListNode(4)
    n1.next = n2
    n2.next = n3
    n3.next = n4
    Solution().deleteNode(n3)
    assert n2.next.val == 4
